<template>
  <div class="box">
    <h1>Child1:{{count}}</h1>
  </div>
</template>

<script>
export default {
    name:'Child1',
    data() {
      return {
        count:0
      }
    },
    mounted() {
     this.$root.$on('getCount',(value) => {
      this.count += value
     })
    },
}
</script>

<style scoped>
    .box{
        background: yellowgreen;
    }
</style>